A portable electronic device may use a battery as a power source. Nowadays, as an electronic device is advanced to a smart device, use of Internet and an application increases and thus a size of a display thereof increases, and a resolution of the display and a performance of a central processor are enhanced, and thus a battery consumption amount increases. Accordingly, in order to charge a battery, the number using a charger naturally increases.
In a method of operating a charger, when the charger is connected to a power supply device (a socket of a wall), the charger advances to a preparation step of supplying charge power through an output terminal, and when a load occurs between a power terminal and a ground (GND) terminal of the output terminal, the charger may recognize this as a situation to perform charge and supply charge power through the output terminal.
However, the charger cannot determine whether a load occurring between the power terminal and the GND terminal of the output terminal is a load according to an abnormal charge request by a foreign substance or a load according to a normal charge request by a charge target device.